Method and apparatus for forming a profile groove in a key blank

ABSTRACT

A method and an apparatus for forming a profile groove in an elongated key blank having a key blade with opposite side surfaces. The profile groove is formed in a surface of the key blank by a punching or a broaching tool with at least one tooth. The punching or broaching tool is forced and guided longitudinally in parallel to the key blank so as to cut out the material of the key blank into the desired profile shape, corresponding to the cross-sectional shape of the at least one tooth. At the same time, the opposite side surfaces portions of the key blank are clamped or held firmly between opposite holding surfaces of a fixture, causing a firm abutment and retaining action on the longitudinal side surface portions of the key blank located adjacent to and all along the profile groove being formed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 USC 119 to SwedishPatent Application No. 1250875-0 filed Jul. 18, 2012 and priority to PCTApplication No. PCT/SE/2013/050669 filed on Jun. 11, 2013 the entirecontents of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for forming aprofile groove in an elongated key blank having opposite side surfaces.

BACKGROUND OF THE INVENTION AND PRIOR ART

The normal way of forming profiles grooves in the sides of a key blankmade of a durable material, such as brass, or so called “nickel silver”,or some other metal alloy, is to use a rotating cutter disc whichoperates in a side surface of the key blank so that the material is cutaway and a groove is formed, while moving the axis of the cutter disclinearly along the key blank.

However, the shape of the profile groove formed by such a conventionalmethod is limited. Of course, the disc can be oriented at an anglerelative to the key blank surface, and it is also possible to modify theshape of the peripheral, active surface of the cutter disc to someextent. Even so, there are numerous geometrical shapes of profilegrooves that need other or additional forming methods, in particularundercut profile grooves of various geometrical shapes.

It is known per se to use linearly guided punching tools with one ormore teeth, such as broaches with several teeth, for making profilegrooves in key blanks. See e.g. the published international patentapplication WO/2010/095997 (WINLOC AG), page 2, last paragraph. Suchtools are guided and forced linearly in parallel to the key blank whileforming a profile groove, such as an undercut groove.

However, there are limitations as to the possible geometrical shapesthat can be made with such punching tools. The forces are very strong,and there is a clear risk that the material of the key blade will startto float adjacent to the groove being formed in this way, especially ifthe wall between the inside of the groove and the outer surface of thekey blank is relatively thin Thus, there is a great risk that the keyblade will be deformed during this forming process, making the finishedkey useless.

Object of the Invention

Against this background, it is an object of the invention to provide amethod and an apparatus that makes it possible to use linearly guidedpunching tools or broaching tools when making profile grooves in keyblanks, without deforming the material of the key blank adjacent to theprofile groove being formed in a surface of the key blank.

It is also an object to provide a method and an apparatus for groovemaking that is suitable for serial production of keys in large numbers,at relatively high speed.

Furthermore, the method and apparatus should be reasonable in cost andeasy to operate.

SUMMARY OF THE INVENTION

A method according to the invention, which overcomes the problemsindicated above, involves the steps of

forming a profile groove in a side or edge surface of a key blank bymeans of a punching or broaching tool with at least one cutting toothwhich is forced and guided longitudinally in parallel to said elongatedkey blade so as to cut out the material of said key blank into thedesired shape of the profile groove, corresponding to thecross-sectional shape of said at least one cutting tooth, while

at the same time holding said opposite side surfaces of the key blankbetween opposite holding surfaces of a fixture, causing a firm abutmentand retaining action on the longitudinal side surface portions of thekey blank located adjacent to and all along said profile groove beingformed, whereby the key blank material adjacent to said profile grooveis retained in a fixed state without being deformed during the punchingoperation.

Correspondingly, an apparatus according to the invention comprises

a longitudinally guided punching or broaching tool with at least onecutting tooth for forced movement longitudinally along the key blank andcutting out said profile groove in the key blank during a punching orbroaching operation,

a fixture provided with a guiding device for longitudinally guiding saidpunching or broaching tool during said punching or broaching process,and

a holding device in said fixture, said holding device having twoopposite holding surfaces adapted to abut against two opposite,longitudinal side surface portions of said key blank during saidpunching or broaching operation, causing an abutment and retainingaction on the longitudinal side surface portions located adjacent to andall along said profile groove being formed, whereby the key blankmaterial adjacent to said profile groove is retained in a fixed statewithout being deformed during said punching or broaching operation.

Preferably, the punching or broaching tool is secured to a slide memberwhich is forced and guided rectilinearly in relation to the fixture. Theslide member may be guided in a longitudinal recess in the fixture, suchas a cavity communicating with a longitudinal passageway leading out tothe holding surface of the fixture abutting against a side or edgesurface of the key blank. The slide member may be provided with a neckportion extending through such a passageway and carrying the punching orbroaching tool.

The profile groove may be formed by a combination of processes, such asan initial forming with a rotating cutting disc and a final forming witha punching or broaching tool. However, it is also possible to form thewhole profile groove in one processing step by means of the punching orbroaching tool.

The punching or broaching tool may be provided with only one cuttingtooth, or be constituted by a broach having two or more cutting teeth.

The profile groove being formed may be located in a side surface or inan edge surface of the key blank.

These and other features of the invention will be apparent from thedetailed description below and from the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in detail below with reference tothe drawings illustrating some preferred embodiments.

FIGS. 1 and 2 illustrate in perspective views the method and apparatusaccording to the invention, with a key blank, a fixture or holdingdevice and a slide member carrying a punching or broaching tool;

FIG. 3A shows a cross-section through the apparatus shown in FIGS. 1 and2;

FIG. 3B shows an enlarged portion of FIG. 3A;

FIG. 4 shows a side view of the apparatus of FIGS. 1 and 2;

FIG. 5 shows a second embodiment of an apparatus according to theinvention, where the key blank is concealed in the fixture but isindicated by dash-dotted lines;

FIG. 6 shows the apparatus of FIG. 5, with an upper clamping or holdingmember being raised to an upper position;

FIGS. 7A, 7B, 7C, 7D, and 7E show various views of a key blank having aninitial profile groove formed by a cutter disc;

FIGS. 8A, 8B, 8C, 8D, and 8E show corresponding views of the key blankof FIGS. 7A through 7E where the profile groove has been expanded intoan undercut portion formed by the method according to the presentinvention;

FIGS. 8A′, 8W, 8C′, 8D′ and 8E′ show corresponding views of the keyblank of FIGS. 8A through 8E where the profile groove has been expandedinto a further undercut portion, the groove being extended also to apart of the gripping portion thereof;

FIGS. 8A″, 8D″, and 8E″ show corresponding views of a key blank beingformed with an undercut profile groove, where the groove extends alongthe whole length of the key blank, including its gripping portion;

FIGS. 9A and 9B show a side view and a perspective view, respectively,of a key blank as shown in FIGS. 8A″ through 8E″ and also provided withcode cuts in its upper edge portion;

FIGS. 10A, 10B, 10C, 10D, and 10E show various views of a key blankbefore any groove is formed therein;

FIGS. 11A, 11B, 1C, 11D and 11E show corresponding views of the keyblank shown in FIGS. 10A through 10E after forming an undercut groove bymeans of a punching or broaching tool in accordance with the presentinvention;

FIGS. 11A′, 11B′, 11C′, 11D′ and 11E′ show corresponding views of thekey blank shown in FIGS. 11A through 11E after forming an additionalundercut portion of the profile groove;

FIGS. 11A″, 11D″ and 11E″ show corresponding views of a key blank withan undercut profile groove formed in one step along the full length ofthereof;

FIGS. 12 and 13 show perspective views of an apparatus according to theinvention, with a large stationary block of a fixture and a relativelysmall movable block serving as a clamping or holding member, the keyblank being oriented so as to stand in a vertical plane during theforming process, and the profile groove formed being located in a loweredge surface of the key blank;

FIGS. 14A, 14B and 14C show side views of three different key blanksbefore forming any profile groove therein;

FIGS. 15A, 15B and 15C show corresponding side views of the key blanksshown in FIGS. 14A, 14B and 14C after forming an undercut profile groovein the side surface of each key blank;

FIGS. 16A, 16B and 16C show the key blanks of FIGS. 14A, 14B and 14Cprovided with a separate gripping member attached to the respective keyblade;

FIG. 17 shows a slide member, similar to the one shown in FIGS. 1 and 2,but having a punching or broaching tool in the form of a broach withseveral teeth arranged longitudinally;

FIGS. 18A, 18A′, 18B and 18B′ show various side views and end views ofthe slide member and the attached broach as shown in FIG. 17; and

FIGS. 18C and 18C′ show top views of the slide member and the attachedbroach of FIG. 17.

DETAILED DESCRIPTION OF SOME PREFERRED EMBODIMENTS

The apparatus shown in FIGS. 1 and 2 comprises a solid fixture with twoclamping or holding members, viz. a lower, stationary holding block 10,and an upper holding block 20, the latter being movable up and down soas to enable the positioning of a key blank 1 on an upper holding orseating surface 11 of the lower block 10, and thereafter lowering theupper block onto the key blank and holding it firmly between the twoblocks 10, 20. The lower block 20 has two side portions 12, 13 extendingupwards from the seating surface 11 and forming between themselves achamber 14 in which the upper block 20 is movable vertically with aslight play. See also FIGS. 3A, 3B and 4.

As appears from FIGS. 1, 2 and 3B, the key blank 1 comprises a flat keyblade, with opposite side surfaces 2, 3, and a grip portion 6.

In the lower position of the movable block 20, as shown in FIGS. 1, 3A,3B and 4, the movable block 20 is held firmly so as to abut the upperside surface 3 of the key blank 1 with a clamping or holding force(arrows A in FIGS. 1, 3A and 4). This force does not have to be verygreat, but the movable block 20 should be maintained in its lowerposition so as to resist any tendency of the key blank to be moved ordeformed during the forming process. In this way, both opposite sidesurfaces 2, 3 (FIG. 3B) of the key blank 1 are maintained exactly intheir initial states or positions and will not be moved or deformed.This is especially true for a ridge portion 8 of the key blank betweenthe side surface 2 and the undercut portion of the groove 4. In order toachieve this, the upper block 20 may be connected to a mechanism, suchas a knuckle joint mechanism being structured in such a way that it willbe maintained exactly in its final operative position upon being loweredto its lowermost position.

While being held firmly in its position between the two blocks 10, 20,the key blank will be cut by a punching or broaching tool 30 secured toa linearly guided slide member 40. During the cutting process, a profilegroove 4 is formed in the key blank, adjacent to its first or lower sidesurface 2. In this way, a pre-formed groove 4 of rectangular shape willbe extended sideways or downwardly (to the right in FIG. 3B) into anundercut groove portion 4 a (FIG. 8C). So, the preformed groove 4 ismade by a conventional rotating cutting disc, whereas the undercutgroove portion 4 a is made by means of the linearly guided punching orbroaching tool 30 according to the present invention. The rectangularprofile groove 4 and its adjoining undercut portion 4 a are clearlyvisible in the FIGS. 7A through 7E (the groove 4) and 8A through 8E (theundercut portion 4 a which stands at right angle to the rectangulargroove 4 in this case). See especially FIGS. 8C and 8E. The undercutportion 4 a, which is also rectangular in shape, adjoins the groove 4 atsome distance from the bottom of the relatively deep groove 4 and isrelatively wide at its innermost part.

The undercut portion of the groove 4 a extends only along the key bladeup to the stopping step surface 5 near the gripping portion 6, along alength L1. Thus, in this embodiment, the undercut portion 4 a will endwith a distinct step surface inside the profile groove 4, whereas theremaining profile groove will end with a curved portion, correspondingto the shape of the cutting disc used when forming the rectangularinitial groove 4. The innermost, undercut portion 4 a of the profilegroove may be used to achieve an axial stop, cooperating with acorresponding rib with a limited length in an associated key plug of acylinder lock (not shown).

In this embodiment (FIGS. 1, 2, 3A, 3B, 4), the punching or broachingtool 30 is provided with one cutting tooth only, at the end of the tool30 (to the left in FIGS. 1, 2 and 4).

The forces appearing when cutting the key blade by the punching orbroaching tool 30 are very great, and it is imperative that the keyblank is held firmly between the blocks 10, 20 and also that the linearguidance of the slide member 40 is very precise. The exact guidance ofthe slide member 40 is accomplished by way of machining or otherwiseforming a longitudinal cavity 15 in the lower block 10 (FIG. 3A), thecavity extending in parallel to the upper seating surface 11 of theblock 10 and to the longitudinal axis of the key blank upon placing thelatter onto the seating surface 11 between the upstanding side portions12, 13 of the lower block 10. Also, the cross-section of the slidemember 40 corresponds exactly to the configuration of the cavity 15,with only a slight play enabling a linear but non-rotatable movement ofthe slide member 40 within the cavity 15. A non-shown drive mechanismwill push the slide member longitudinally in the direction of the arrowB (FIGS. 1 and 2) with a great force, in order to carry out the cuttingprocess of the punching or broaching tool 30. The drive mechanism may beconstituted e.g. by a mechanical drive mechanism, an electro-mechanicaldrive mechanism, a pneumatic drive mechanism, or a hydraulic drivemechanism, as will be selected by those skilled in the art of generalmachinery.

The punching or broaching tool 30 must be thinly secured to the slidemember 40, and this is achieved by a longitudinally extending neckportion 41 which is adapted to connect the slide member 40 with thepunching or broaching tool 30 and which fits with a slight play in alongitudinal passageway 16 (FIGS. 1 and 2) formed in the lower block 10adjacent to the cavity 15. The cavity 15 has a substantially rectangularcross-sectional configuration, with rounded edges, whereas thepassageway 16 and the corresponding neck portion 41 have an upwardlytapering cross-section that will ensure a strong and durable connectionto the punching or broaching tool 30.

Preferably, the slide member 40 and the cutting tool are made in onepiece, but it is also possible to weld or screw them together.

In FIG. 3B it will be seen that the upper, cutting part of the punchingor broaching tool 30 is formed with the same cross-sectionalconfiguration as the desired cross-section of the undercut portion 4 aof the profile groove.

In case the profile groove 4 is to be provided with a further undercutportion, it is feasible to use a modified punching or broaching toolhaving at least one further tooth having a configuration correspondingto the desired shape of the further undercut portion 4 aa, as shown inFIGS. 8A′, 8B′, 8C′, 8D′ and 8E′. The further undercut portion 4 aaadjoins an undercut portion 4 a corresponding to the undercut portion 4a in the previous embodiment.

In this case, the profile groove 4 extends along the whole length of thekey blade and along the major part of the gripping portion 6, along atotal length L2 up to a hole in the gripping portion.

Another key blank is shown in FIGS. 8A″, 8D″ and 8E″. In this case, theprofile groove 4 with its undercut portion 4 a extends along the fulllength L3 of the key blank 1, including the gripping portion 6 thereof.Here, the cross-section of the profile groove is the same all along thekey blank, as will be seen in FIGS. 8A″ and 8E″.

In FIGS. 5 and 6, there is shown a modified embodiment of the grooveforming apparatus including an upper, movable block 20′ and a lower,stationary block 10′ configured to receive a key blank 1 (oriented lyingflat on a seating surface 11′ as in FIGS. 1 and 2) between two rathershallow upstanding side portions 12′, 13′ and with a projecting portion17 fitting into a hole 9 in the grip portion 6 of the key blank.

The height of the upstanding side portions 12′, 13′ is substantially thesame as (or slightly less than) the thickness of the key blank 1, sothat the key blade 1 will be firmly held in place by the upper block 20′when the latter is pressed down. Then, the planar lower surface(notvisible in FIGS. 5 and 6) clamps onto the key blank 1 and possiblyalso onto the lower block 10′ (arrows A in FIG. 6).

The structure and function of the punching or broaching tool 30 and theslide member 40 are the same in this embodiment as in the previous one.The only difference is the configuration of the two blocks 10, 20 and10′, 20′, respectively.

Of course, a key blank formed as described above is not a finished key.Rather, as is well-known in the art, it should be provided with somecode pattern cooperating with tumblers in an associated cylinder lock(not shown). Such codes can be forming e.g. along the profile groove, soas to cooperate with side tumblers in the lock, and/or at a longitudinaledge 7, as shown in FIGS. 9A and 9B (where the edge cuts will cooperatewith regular tumbler pins in a lock).

As indicated above, it is also possible to form an under-cut profilegroove in one manufacturing step by using a broach having a number ofcutting teeth. Various resulting key blanks are shown in FIGS. 11Athrough 11E, FIGS. 11A′ through 11E′ and FIGS. 11A″, 11D″ and 11E″, theprofile grooves being formed in one step in a key blank 1′ as shown inFIGS. 10A through 10E and having no initial profile groove at all.Accordingly, the whole profile groove is formed in one step with abroach being forcedly guided along the key blade 1′.

Depending on the shape of the profile groove, the broach 30′ is providedwith a number of teeth 31′, 32′, 33′, 34′, etc. (see FIGS. 18A′ and18C′), where each successive tooth is displaced or extended somewhat inrelation to the previous one. In this way, each tooth will cut away anadditional amount of material in the key blank, and a rather complicatedgeometrical configuration can be obtained. Compare also the end view inFIG. 18B′ showing the complete configuration or contour of the profilegroove.

An advantage with the embodiment shown in FIGS. 17, 18A, etc. is thatthe profile groove can be manufactured in one step, which makes theproduction quicker and less costly.

The invention may be implemented in various ways. An alternative groovemaking apparatus is shown in FIGS. 12 and 13. The main difference inrelation to the embodiments shown in FIGS. 1, 2, 5 and 6 is that themovable block 20″ is moved sideways (arrows C) against an upstandingportion 13″ of the stationary, lower block 10″ and that the key blank isoriented with its central plane standing vertically. Here, the profilegroove is formed in the lower edge surface of the key blank 1. It isimportant that the opposite side surfaces of the key blank adjacent toits lower edge, are held firmly in place all along the edge surface inwhich the profile groove is being cut by means of the punching orbroaching tool.

Otherwise, this apparatus, with the slide member 40 and the punching orbroaching tool 30, operates basically in the same way as in the previousembodiments.

Although not shown in the drawings, the cavity 15 which guides the slidemember 40 may be formed as an open recess in the lower block 10,preferably with undercut side portions serving to hold the edge portionsof the slide member in place vertically, or it may be acircumferentially closed cavity. In the latter case, the key blank willhave to be inserted into the cavity as well, possibly together with aninsert member fitting precisely into the cavity together with the keyblank. In such a case, there will be no movable block of the fixture,other than the insert member which is positioned axially into thecavity. It seems more practical, however, to have two blocks, one ofwhich is movable vertically or transversely in relation to the other.

It may be possible to use a fixture with only one block having a recessat the top, with a seating surface for one (lower) side of the keyblank, and longitudinal gripping teeth or ribs which engage withportions of the other (upper) side of the key blank. The risk offloating material on this upper side is lower, so such a fixture mayalso be useful, at least in case the profile groove in said one (lower)side of the key blank is rather shallow, e.g. less than half of thethickness of the key blade.

The key blank 1 may have a grip portion 6 a, as shown in FIG. 14A (andin the other drawing figures of the embodiments described above), or itmay have a base portion 6 b or an extended portion 6 c of the key bladewhich may be attached to a separate gripping member 6, as shown in FIGS.16A, 16B and 16C. In either case, the key blank 1 a, 1 b, 1 c may beprovided with a profile groove 4 by means of an apparatus and a methodas described above (before attaching the gripping separate member).

The exact shape of the profile groove may be selected as desired. Theremay be minor irregularities in the cross-sectional configuration, and itis also possible to leave rather thin walls between an undercut portionof the profiled groove, internally of a ridge portion, and the externalside of such a ridge portion (which may form a part of side surface ofthe key blank).

In particular, it is possible to form profile grooves having anygeometrical shape as disclosed in the international patent applicationpublished in WO2010/096009 (WINLOC AG).

Thus, the inventive method and apparatus will give a wide freedom indesigning new keys for cylinder locks, with one or more profile grooveswith or without an undercut groove portion.

Also, with a broach having a multitude of teeth, it is possible to cut acomplicated shape of a profile groove in a single manufacturing step,which makes the production quick and not very expensive, at least whenproducing large number of key blanks.

The invention claimed is:
 1. A method of forming a profile groove in anelongated key blank having a key blade with opposite side surfaces, saidmethod comprising: forming said profile groove in a surface of said keyblank by means of a broaching tool with at least one tooth which isforced and guided longitudinally in parallel to said elongated key blankso as to cut out material from said key blank into a desired profileshape, corresponding to a cross-sectional shape of said at least onetooth, said profile groove extending in a predetermined area from adistal end of the key blade towards a grip portion of the key blade,while at the same time holding said opposite side surfaces of the keyblank between opposite holding surfaces of a fixture, causing a firmabutment and retaining action on the longitudinal side surface portionsof the key blade located adjacent to and all along said profile groovebeing formed, whereby the key blank material adjacent to said profilegroove is retained in a fixed state without being deformed during thebroaching operation.
 2. The method defined in claim 1, wherein saidbroaching tool is secured to a slide member which is forced and guidedrectilinearly in relation to said fixture.
 3. The method defined inclaim 2, wherein said slide member is guided in a longitudinal recess insaid fixture.
 4. The method defined in claim 1, wherein said fixturecomprises a stationary first holding member provided with a firstholding surface, and a movable second holding member provided with asecond holding surface, said second holding member being pressed againstsaid first holding member during said broaching operation.
 5. The methoddefined in claim 1, wherein said profile groove has at least oneundercut portion defined by an inner bottom wall and an opposite wall onan inside of a ridge portion, an outside of which forms at least a partof said longitudinal side surface portions being held by said fixtureduring said broaching operation.
 6. A broaching apparatus for forming aprofile groove in an elongated key blank, comprising: a longitudinallyguided broaching tool with at least one tooth for forced movementlongitudinally along the key blank and cutting out said profile groovein said key blank during a broaching operation, said profile grooveextending in a predetermined area from a distal end of the key bladetowards a grip portion or the key blade, a fixture provided with aguiding device for longitudinally guiding said broaching tool duringsaid broaching operation, and a holding device in said fixture, saidholding device having two opposite holding surfaces adapted to abutagainst two opposite, longitudinal side surface portions of said keyblank during said broaching operation, causing an abutment and retainingaction on the longitudinal side surface portions located adjacent to andall along said profile groove being formed, whereby the key blankmaterial adjacent to said profile groove is retained in a fixed statewithout being deformed during the broaching operation.
 7. The broachingapparatus defined in claim 6, wherein said guiding device comprises aslide member being longitudinally guided in said fixture, said broachingtool being secured to said slide member.
 8. The broaching apparatusdefined in claim 7, wherein said broaching tool is integrated in onepiece with said slide member.
 9. The broaching apparatus defined inclaim 7, wherein said slide member is connected to said broaching toolvia a neck portion which is movable in a passageway between said holdingdevice and a guiding recess in said fixture.
 10. The broaching apparatusdefined in claim 9, wherein said guiding recess is a longitudinalguiding cavity in said fixture, said cavity being dimensioned toaccommodate said slide member with a slight play enabling a linear butnon-rotatable movement in parallel to said key blank when being held insaid holding device of said fixture.
 11. The broaching apparatus definedin claim 6, wherein said broaching tool is forcedly movable along one ofthe following: at least a part of a length of said key blank, at least afull length of said key blank up to a gripping portion, and the fulllength of said key blank, including said gripping portion.
 12. Thebroaching apparatus defined in claim 6, wherein said holding devicecomprises two opposite holding members, a first one being stationary andprovided with a first holding surface, and a second one being movableand provided with said second holding surface, so as to clamp and holdsaid key blank during said broaching operation.
 13. The broachingapparatus defined in claim 12, wherein said movable second holdingmember is pressed against said stationary first holding member by one ofthe following drive mechanisms: a mechanical drive mechanism, anelectro-mechanical drive mechanism, a pneumatic drive mechanism and ahydraulic drive mechanism.
 14. The broaching apparatus defined in claim6, wherein said broaching tool has only one tooth.
 15. The broachingapparatus defined in claim 6, wherein said punching tool is a broachhaving two or more teeth.